1. Field of the Invention
The present invention relates to a method and apparatus for automatically dispensing segments of a web of one or more layers of fiber-reinforced composite material from spools, as well as the placement and shaping of the web segments to contoured surfaces of a tool, prior to curing of the web segments on the tool in an autoclave or other curing apparatus.
2. Description of the Related Art
Apparatus for the manufacture of structural members from layers of composite materials, fiber-reinforced or otherwise, is well-known. Such apparatus, however, has a variety of drawbacks.
Automated tape layer (ATL) apparatus places single layers of uncured composite pre-impregnated unidirectional tape on a flat or near-flat contoured surface. Compaction pressure, and if necessary, heat is applied to cause the layers of the material to be consolidated prior to curing.
However, ATL apparatus has proven to be unsatisfactory; the tape webs exhibit non-elastic behavior, the web path lengths change due to tool contours, the ATL apparatus is only capable of single layer placement and there is no final forming to shape.
Automated fiber placement (AFP) apparatus is also known in which single layers of uncured composite pre-impregnated unidirectional tape can be placed on severely contoured surfaces. Numerous individual yarns of uncured pre-impregnated structural fiber can be applied to the contoured surfaces. Each yarn is controlled to feed at such a rate that the dispensed yarn length matches the web path length due to the tool contour changes.
Compaction of the material is also performed at the head, thus causing consolidation of the material during lay-up. However, AFP apparatus is also undesirable; many types of composite pre-impregnated materials are not available in yarn form, the apparatus is able to place only a single layer at a time, and there is no final forming to shape.
Still another known apparatus performs automated filament winding. This machinery provides the placement of single yarns of uncured composite pre-impregnated unidirectional material on contoured surfaces of a tool that rotates about its central axis as a yarn or filament is dispensed from a dispensing head. Compaction is accomplished with a compaction head and heat if needed. This apparatus has the same drawbacks as the AFP apparatus, and in addition requires the tool configuration to be mounted on a rotating mechanism.
Against this background of known prior art, applicants have developed a new, more efficient, speedier, and cost-effective process for building fiber-reinforced structural members from multiple layers of composite material.